Ball joint seat assembly



Dec. 28, 1965 s. SULLIVAN, JR

BALL JOINT SEAT ASSEMBLY Filed 001;. 22, 1962 INVENTOR Lea S. Sullivan,

His Affor ney United States Patent 3,226,141 BALL JGINT SEAT ASSEMBLYLeo S. Sullivan, Jr., Dayton, Ohio, assignor to General MotorsCorporation, Detroit, Mich, a corporation of Delaware Filed Oct. 22,1962, Ser. No. 232,165 2 Claims. (Cl. 28787) This invention relates to aball joint seat assembly, and more particularly, to an integral ballseat and retaining means in combination therewith.

An object of this invention is to provide a new and improved ball jointseat assembly that provides simultaneously for preloading the ball,self-adjustment for wear compensation as well as minimizing any need forlubrication maintenance.

Another object of this invention is to provide a ball joint seatassembly including a stud carrying a curved head portion to fit in ahousing portion with a cylindrical cavity therein to be closed off bycover means and also adapted to receive a combination preloading andwearcompensating low-friction bearing seat portion that includes anannular body of low-friction resilient material having a curved innerperiphery as well as an outwardly flared flange end having radial slitslocated axially therein at predetermined locations and adapted to befitted within the cylindrical cavity of the housing portion.

Another object of this invention is to provide a method of preloading aball joint seat retainer assembly to increase bearing capacity thereofand simultaneously providing wear compensation by steps of tapering anouter periphery of one end of a ball seat having a curved innerperiphery at an opposite end thereof, radially slitting the ball seatlongitudinally along said tapering location, heating the ball seat to apredetermined temperature to increase ductility thereof, snapping theball axially into place with an integral stud thereof projecting awayfrom said tapering, pressing the ball and seat into a socket-like recesswhile simultaneously urging radially inwardly the outer taperingperihpheral end of the ball seat into the preloading, increased bearingcapacity and wear compensating condition, and finally covering thesocket-like recess at a location remote from the stud projectingtherefrom.

A further object of this invention is to provide a method of preloadinga ball joint seat retainer assembly to increase bearing capacity thereofand simultaneously providing wear compensation by steps of tapering anouter flared peripheral end of a ball seat having a curved innerperiphery at an opposite end thereof, radially slitting alternate deepand shallow slots into the ball seat longitudinally along said taperinglocation, heating the ball seat to a predetermined temperature such asin oil at substantially 180 F. to increase ductility thereof, snappingthe ball axially into place with an integral stud thereof projectingaway from said tapering, pressing the ball and seat into a socket-likerecess while simultaneously urging radially inwardly the outer taperingflared peripheral end of the ball seat into the preloading, increasedbearing capacity and wear compensating condition, and finally coveringthe socket-like recess at a location remote from the stud projectingtherefrom.

Another object of this invention is to provide a ball joint assemblyincluding a stud carrying a curved head portion chromed to avoidpossible corroding thereof in service as well as a combinationpreloading and wearcompensating low-friction bearing seat portion ofDelrin acetal resin with Teflon fluorine-containingpolytetrafluor-oethylene fibers mixed therein for minimum lubricationrequirements accompanied by resiliency and moldability, the bearing seatportion including an annular body having a curved inner periphery at oneend as well as an outwardly flared opposite flange end having radialslits of alternately deep and shallow configuration located axiallytherein and adapted to be fitted within a cylindrical cavity of ahousing portion with an inner diameter less than that of the outwardlyflared flange end, the deeper slits extending into the curved innerperiphery of the annular body so as to permit proper preloading and wearcompensating fit to the curved head portion snapped into complementaryfit with the curved inner periphery of the annular body.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred embodiment of the present invention isclearly shown.

In the drawings:

FIGURE 1 is a partially sectioned view of a ball joint seat assembly inaccordance with the present invention.

FIGURE 2 is a cross-sectional view taken along line 22 in FIGURE 1.

FIGURE 3 is an end view of a ball seat per se having features inaccordance with the present invention.

FIGURE 4 is a cross-sectioned elevational view taken along line 4-4 inFIGURE 3.

FIGURE 1 is a partially sectioned view of a ball joint seat assemblygenerally indicated by numeral 10. The assembly 10 as illustrated inboth FIGURES 1 and 2 includes a laterally extending threaded stud 11adapted to be secured as a vehicle linkage tie rod end. The threadedstud 11 is integral with a housing portion 12 as seen in FIGURE 2. Thehousing portion 12 includes a cylindrical cavity 13 therein thatcommunicates with an axial passage or opening 14 extending therefrom asshown in FIGURE 2.

A bellows-like resilient boot member 15 can have a flanged end 16thereof fitted peripherally over a shoulder 17 of the housing portion 12such that a spring metal clamping means 18 with radially outwardlyprojecting free ends 19 can be in snap-fit tight engagement foranchoring therewith. An expansion spring means 20 can be provided tourge the boot member 15 upwardly as indicated in FIGURE 2 and a radiallyinwardly projecting seal end 21 of the boot means can engage a conicallytapered stud means 22 carried by a ball or curved head portion 24chromed for corrosion resistance. Additional corrosion resistance can beprovided by packing the assembly with a suitable lubricating materialretained by the bellows-type dirt-shielding boot sealing member 15. Suchlubricant packing can be provided initially during manufacture and nofurther lubrication is to be required during service and operation ofthe subject ball joint seat assembly as a result of an improved ballseat per se generally indicated by numeral in views of FIGURES 2, 3 and4.

The ball seat per se includes an annular body 31 of low-frictionresilient material having a curved inner periphery 32 at one end as wellas an outward flared opposite end 33. The diameter of the cylindricalcavity 13 of the housing portion 12 is less than outer diameter of theoutwardly flared flange end 33. The low-friction resilient material forthe ball seat per se 30 can consist of a compounding of Delrin acetalresin with Teflon fluorine-containing tetrafluoroethylene fibers mixedtogether for both resiliency and moldability. The fluorinecontainingfibers eliminate need for periodic lubrication.

In the ball seat per se there can be provided a plurality of cuts orslits at least some of which extend from one end into the curvedperiphery 32. In the embodiment shown in views of FIGURES 2, 3 and 4 ofthe drawings, there are radial slits of alternately deep and shallowconfiguration located axially in the ball seat and extendinglongitudinally from the flared flange end 33 thereof. As indicated inFIGURE 4, there can be deep slitting 34 as well as shallow slitting 35alternately at predetermined locations such that a plurality of segments36 are formed therebetween and are adapted to be displaced radiallyinwardly as permitted by the slitting 3435 for preloading as well aswear-compensating purposes. It is to be noted that alternate deep andshallow slitting can be located at diametrically opposite locations asshown in FIGURE 3 such that the segments 36 therebetween have one endintegral with the annular body 31 providing therewith an integral ballseat and retaining means for the curved head portion 24 as indicated inFIG- URE 2.

Essential for the present method of preloading the ball joint seatretainer assembly to increase bearing capacity thereof andsimultaneously providing wear compensation, the following steps areincluded during manufacture of the ball joint seat assembly. These stepsinclude tapering the outer flared peripheral end 33 of the ball seat perse having the curved inner periphery 32 at an opposite end thereof. Thenthere is radial slitting of alternately deep and shallow slots 3445 intothe ball seat per se longitudinally along the tapering location. Thistapering on the outside of the ball seat starting at a location to oneside of the spherical or curved inner periphery 32 permits preloading ofthe ball or curved head portion 34 therewith. This tapering combinedwith the radially and longitudinally extending slots or slits in theseat per se can be effective in causing at least part of the bodyportion 31 having the spherical or curved inner periphery thereof to beforced radially onto the ball or curved head portion once the ball seatand headed stud as assembled to each other are pressed into the balljoint housing, such as for a tie rod and retainer assembly. Additionalpreloading is accomplished by the angle along the outwardly flared endto place the segments such as 36 in a bending attitude due to provisionof the radial slots or slits 34-35 in the ball seat.

Assembly of the stud and head portion into the seat is accomplished by astep of heating the seat per :se in a hot liquid medium such as oil,water and the like at a temperature of substantially 180 F. to increaseductility of the resin material of the ball seat per se followed bysnapping the ball or curved head portion 24 into place relative to thecurved inner periphery 32. Use of oil for heating the seat per se 30 canbe advantageous since'this will provide a preliminary lubrication forboth inner and outer surfaces thereof to facilitate press fitting of thecombined ball and seat assembly into confines of the cylindrical cavity13 having the diameter thereof less than that of the outwardly flaredperipheral end 33. As can be seen in FIGURE 2, the ball seat with thecurved head portion 24 therein is assembled to the housing portion 12.such that the stud 22 projects through the opening 14- and is engaged bythe sealing end 21 of the boot member. The outwardly flared end 33 isforced radially inwardly such that the segments 36 provide preloading aswell as wear compensation and resilient retention of the curved headportion 24 inwardly thereof.

A final step of covering the socket-like recess or cylindrical cavity 13occurs by attachment of a plug or centrally embossed cover means 37against the periphery end 33 subject to spinning or peening over aflange 38 radially inwardly and integrally with the housing portion 12as shown in FIGURE 2.

It is to be noted that use of a circular Wave or marcel spring for axialbias per se can be provided centrally as to the embossed cover means 37through use of any spring axially of the opposite ends of the ball seatper se would not provide the radially inward preloading as permitted bythe outwardly flared tapered end having the slots or slits radially andextending longitudinally thereof for elimination of looseness previouslyencountered after use of a vehicle for a relatively low mileage.Repeated lubrication is avoided for life of a steering linkage due touse of Delrin acetal resin with Teflon polytetrafluoroethylet e fiberschopped and mixed into the composition molded to have the annular bodyand integral outwardly flared end with slots or slitting therein toprovide both preloading as well as self-adjusting features for weartake-up.

As can be seen best in FIGURE 4, the tapered end projects outwardly byan angle of at least 5 as represented by an are A as well as downwardlyby an angle of at least 10 as represented by an arc B and an oppositeconical ending 39 having an angle of substantially 30 from thecylindrical outer periphery of the body 31 can be provided. When theball seat per se 30 is installed in a socket as represented in FIGURE 2,it is apparent that then the tapered end is forced radially inwardly byat least 5 leaving a difference between the arcs A and B due to theinward bending with a resultant 5 downward projection of the lowerperiphery of the tapered end. This 5 resultant difference assures addedpreloading of the tapered portion due to engagement of this tapered endby the periphery of the cover 37 as indicated in FIGURE 2 thereby addinga preloading which assures maintenance of the segments such as 36 in abending attitude for wear take-up simultaneously with the preloading.Preloading the ball or curved head portion 24 by use of the ball seatper se 30 also increases bearing capacity while simultaneously providinga means of wear compensation as well as resilient retention of thecomposition bearing material between the head portion 24 and housingportion 12.

While the embodiments of the present invention as herein disclosedconstitute a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

1. A ball joint seat assembly, comprising, a stud having a curvedsubstantially segmental spherical head portion, a cover means centrallyembossed so as to be complementary to said curved head portion, ahousing portion receiving said stud and having a substantiallycylindrical cavity therein that terminates in a reduced end openingthrough which said stud projects away from said cover means, said covermeans carried by the housing end portion opposite said reduced opening,and a combination preloading and wear compensating low-frictionresilient bearing liner seat portion in said cavity between said reducedend opening and said cover means, said liner including an annular bodyhaving a curved substantially segmental spherical inner periphery at oneend engaging said curved head as well as an outer periphery at the otherend which has an initially radially outwardly flared peripheral endportion prior to assembly, and also a plurality of different sized slitsdefining segments between said slits which extend longitudinally withsaid radially outwardly flared peripheral end portion, the flared outerperiphery of said end portion prior to completion of joint assemblyextending at an angle of substantially 5 outwardly from the outerperiphery of said annular body so as to provide an outer diameter on theend portion of the liner greater than the inner diameter of thecylindrical cavity, one end of the liner adjacent the flared peripheryinitially extending at an angle of substantially 10 downwardly away fromthe axis of the cylindrical cavity from a reference plane that isperpendicular to the axis of the hearing liner and cylindrical cavity,said liner having a complementary telescopic fit into the cylindricalcavity with said outwardly flared peripheral end portion being forcedtherein during assembly, such that inward preload occurs due todisplaced confinement of the 5 and 10 angular portions of said liner endengaged in assembly by said cylindrical cavity of said body portion andsaid cover means respectively assembled thereto.

2. The assembly of claim 1, said slits being alternately deep andshallow with at least some thereof extending into the curved innerperiphery of the liner body that engages the head portion.

(References on following page) References Cited by the Examiner3,089,198 5/ 1963 Eirhart 2879O X Fadow X 1,960,956 5/1934 Riedel29-1495 FOREIGN PATENTS 2,252,351 8/1941 Paulus 29149.5 5 720,912 5/1942Germany- 2,350,398 6/1944 Hufferd. 725 724 3/1955 G t B 2,393,501 1/1946Brown. 3 Tea m 2,890,041 6/1959 Runton et a1 308238 X Eh 1 18 6242,903,535 10/1959 Runton et a1. 308238 X German aPP canon )1 1 Prmted 10November 11, 1961, (KL,63C47). 2921808 1/1960 Dav! 287*87 X D 11inacetal resi ublished June 1957 1) P01 ch 2,976,068 3/1961 Jordan 287-906 P Y Y 3,004,786 10/1961 Herbenar 287-90 1531;13 :23 5 1255,555 and(Inc') 3,037,893 6/1962 White.

3,063,744 11/1962 Flumerfiet. 15 CARL W. TOMLIN, Primary Examiner.

1. A BALL JOINT SEAT ASSEMBLY, COMPRISING, A STUD HAVING A CURVEDSUBSTANTIALLY SEGMENTAL SPHERICAL HEAD PORTION, A COVER MEANS CENTRALLYEMBOSSED SO AS TO BE COMPLEMENTARY TO SAID CURVED HEAD PORTION, AHOUSING PORTION RECEIVING SAID STUD AND HAVING A SUBSTANTIALLYCYLINDRICAL CAVITY THEREIN THAT TERMINATES IN A REDUCED END OPENINGTHROUGH WHICH SAID STUD PROJECTS AWAY FROM SAID COVER MEANS, SAID COVERMEANS CARRIED BY THE HOUSING END PORTION OPPOSITE SAID REDUCED OPENING,AND A COMBINATION PRELOADING AND WEAR COMPENSATING LOW-FRICTIONRESILIENT BEARING LINEAR SEAT PORTION IN SAID CAVITY BETWEEN SAIDREDUCED END OPENING AND SAID COVER MEANS, SAID LINER INCLUDING ANANNUULAR BODBY HAVING A CURVED SUBSTANTIALLY SEGMENTAL SPHERICAL INNERPERIPHERY AT ONE END ENGAGING SAID CURVED HEAD AS WELL AS AN OUTERPRIPHERY AT THE OTHER END WHICH HAS AN INITIALLY RADIALLY OUTWARDLYFLARED PERIPHERAL END PORTION PRIOR TO ASSEMBLY, AND ALSO A PLURALITY OFDIFFERENT SIZED SLITS DEFINING SEGMENTS BETWEEN AND SLITS WHICH EXTENDLONGITUDINALLY WITH SAID RADIALLY OUTWARDLY FLARED PERIPHERAL ENDPORTION, THE FLARED OUTER PERIPHERY OF SAID END PORTION PRIOR TOCOMPLETION OF JOINT ASSEMBLY EXTENDING AT AN ANGLE OF SUBSTANTIALLY 5*OUTWARDLY FROM THE OUTER PERIPHERY OF SAID ANNULAR BODY SO AS TO PROVIDEAN OUTER DIAMETER ON THE END PORTION OF THE LINER GREATER THAN THE INNERDIAMETER OF THE CYLINDRICAL CAVITY, ONE END OF THE LINEAR ADJACENT THEFLARED PERIPHERY INITIALLY EXTENDING AT AN ANGLE OF SUBSTANTIALLY 10*DOWNWARDLY AWAY FROM THE AXIS OF THE CYLINDRICAL CAVITY FROM A REFERENCEPLANE THAT IS PERPENDICULAR TO THE AXIS OF THE BEARING LINER ANDCYLINDRICAL CAVITY, SAID LINER HAVING A COMPLEMENTARY TELESCOPIC FITINTO THE CYLINDRICAL CAVITY WITH SAID OUTWARDLY FLARED PERIPHRAL ENDPORTION BEING FORCED THEREIN DURING ASSEMBLY, SUCH THAT INWARD PRELOADOCCURS DUE TO DISPLACED CONFINEMENT OF THE 5* AND 10* ANGULAR PORTIONSOF SAID LINEAR END ENGAGED IN ASSEMBLY BY SAID CYLINDRICAL CAVITY OFSAID BODY PORTION AND SAID COVER MEANS RESPECTIVELY ASSEMBLED THERETO.